Rename to clnl, add documentation

[clnl] / src / main / random.lisp

diff --git a/src/main/random.lisp b/src/main/random.lisp
index 44a1a2af0531f6d48e40109cbfa04f9283369bc1..6f500a979558a57fdd519d4323878ab43a5e8052 100644 (file)
--- a/src/main/random.lisp
+++ b/src/main/random.lisp
@@ -1,4 +1,4 @@
-(in-package #:cl-nl.random)
+(in-package #:clnl-random)
 
 ; This is a wrapper around the very nice mersenne twister mt19937 to match
 ; NetLogo's implementation that tries to match how java.util.Random works
@@ -7,7 +7,10 @@
  (setf mt19937:*random-state* (mt19937::make-random-object :state (mt19937:init-random-state n))))
 
 (defun next-int (n)
- (rem (ash (mt19937:random-chunk mt19937:*random-state*) -1) n))
+ (if
+  (= n (logand n (- n) ))
+  (ash (* n (ash (mt19937:random-chunk mt19937:*random-state*) -1) ) -31)
+  (rem (ash (mt19937:random-chunk mt19937:*random-state*) -1) n)))
 
 (defun next-double (&optional (n 1d0))
  (let
@@ -27,6 +30,6 @@
      'list
      (lambda (x) (if (logbitp (1- 32) x) (dpb x (byte 32 0) -1) x))
      (mt19937::random-state-state mt19937:*random-state*))))
-  (format nil "0 ~A ~A ~A 0.0 false 1 ~{~A~^ ~}"
+  (format nil "0 ~A ~A ~A 0.0 false ~{~A~^ ~}"
    (first state) (second state) (third state)
-   (nthcdr 4 state))))
+   (nthcdr 3 state))))